For many years, municipal water systems have used chlorine in the water to disinfect the water prior to its introduction to the distribution system for ultimate consumer use. The chlorine has been introduced in several different forms, depending upon the particular treatment system used in the municipality. One of the more common forms for chlorine introduction has been through the use of hypochlorites, such as sodium hypochlorite.
In recent years, various agencies have discovered that chlorine has not always been adequate for disinfecting water before its introduction into the water distribution systems. Most notably, older water systems which have been in use for many years have experienced a reduction in the germicidal action of chlorine. The chlorine is not effective in long line systems and those with extensive corrosion buildups, as the chlorine treatment tends to weaken under such conditions to levels which are ineffective for bacterial control.
Further, when chlorine alone is used, it may react under certain situations with tannins and lignins present in the water to form trihalomethanes which are suspected carcinogens.
For these reasons, some municipal water treatment systems have begun to add "chloramines" to the water as a germicide. Chloramine is a combination of ammonia and chlorine which is very stable, and has the chemical formula NH.sub.2 Cl. Indeed, some water treatment systems have been ordered by federal agencies to add chloramine to the water systems in order to provide safe levels of germicidal activity. However, there does not appear to be any standard concentration of added chloramine, and while some water systems add chloramine at a concentration of about 0.2-1.0 ppm, others use higher concentrations in the range of 3.0-10.0 ppm. Isolated cases have appeared where concentrations as high as 20 ppm have been found.
Chloramine does not dissipate as rapidly as chlorine over time, and does not break down as rapidly as chlorine when exposed to sunlight. When dissolved in water, chloramine is a potent germicide. Thus, the chloramine has a beneficial effect in the water supply system.
However, it also has an undesirable aspect associated with its use in water. In particular, chloramine is very toxic to fish. When chloramines are added to a tank of fish, the fish will almost certainly die. Death is caused by anemia created in the fish from exposure to chloramine, which results from the chloramine molecule passing the gill membrane and entering the circulatory system of the fish. Depending on the amount of chloramine in the water, death may be quick or belated.
Fish keepers such as importers, breeders, fish shop owners and hobbyists are finding that commercially available chlorine removers will not remove chloramine from the water, due to its strong chemical bonding and stability in the aqueous system. Of course this high stability is also one of the reasons that chloramine is used in the first place.
In many instances, such as in Fort Lauderdale, Fla. and elsewhere, serious financial loss has occurred, causing grievous damage to fish keepers due to the presence of chloramine in the municipal water supply.
Chloramine can also be produced when ammonia and chlorine are added jointly to the water, as for example water in which life forms are present, such as in aquariums and in swimming pools.
It is known that chloramine may be broken down by reacting with sodium thiosulfate generally according to the following reaction: EQU 2Na.sub.2 S.sub.2 O.sub.3 +NH.sub.2 Cl+2H.sub.2 O.fwdarw.Na.sub.2 S.sub.4 O.sub.6 +NH.sub.4 OH+NaOH+NaCl
The foregoing reaction is highly pH dependent, and changes in the pH can alter the stoichiometry of the reactions. Essentially, however, the thiosulfate reacts with the chloramine to produce sodium chloride and ammonium hydroxide in aqueous solution.
The sodium chloride and sulfur hexaoxide produced are in such quantities as to be harmless to fish. However, the ammonia must also be removed in order to prevent its recombination with chlorine to regenerate the chloramine and stop any burning of the gills of fish. This ammonia removal requires another step with a suitable ammonia adsorber. However, such ammonia adsorption is usually quite slow, and thus not feasible for commercial or consumer use.
Thus the prior art process involves two steps coupled with careful control to ensure that all chloramine is reacted fully to form harmless chloride and then to ensure that all ammonia is removed. Such controls, however, are ordinarily beyond the capability of those having the need for the process.
Accordingly, a primary object of the present invention is to provide a novel product for the removal of chloramine from water.
Another object of the invention is to provide an easily usable product and method for removing chloramine from water.
A further object of the invention is to provide a product which can be used in but a single step for removing the chloramine from water and removing the undesirable products of reaction as well.
Still another object of the invention is to provide a novel product and method for removing chloramine from water which may be used quickly and easily by unskilled persons.
These and other objects of this invention will become apparent when considered in light of the following specification and claims.